ANNALS 



OF 



PHILOSOPHY. 



MARCH, 1324. 



Article I. 



On the Crystalline. Forms of' Artificial Salts. 

 By H.J. Brooke, Esq. FRS. 

 (Continued from p. 117.) 

 Tartrate of Potash. 

 The primary form is a right oblique 

 angled prism, with cleavages parallel to 

 the lateral planes. 



M on T 89° 30' 



M one 142 13 



M on b 107 30 



Tone 127 17 



Ton V 103 40 



Bitartrate of' Potash. 

 It has been already observed by Dr. Wollaston, that the 

 cleavages of the crystals of this salt are parallel to the lateral 

 planes and diagonals of either a rectangular or a rhombic prism. 

 From the figures and measurement of seve- 

 ral crystals, I am indncedto adopt the right 

 rhombic prism as the primary form. The 

 annexed figure represents the planes which 

 occur on many of the crystals placed symme- 

 trically in relation to the primary planes. 



MonM' 107° 30' 



M on h 126 15 



M on 6 117 2 



conh 125 30 



cone' 109 



b on V" 77 



New Series, vol. vii. m 



